The present invention relates to a drilling apparatus for tapping into a fluid containing vessel. The present invention further preferably relates to the drilling apparatus tapping into the vessel from a valve device connected with the vessel.
Following the placement of a vessel, such as a pipe, on or beneath the ground surface, it may be necessary or desirable to make a connection with the vessel or to enter the vessel at a location where a hole or opening does not pre-exist. The operation of drilling or cutting a hole or opening in the vessel to facilitate the desired connection is often complicated by the presence of various fluids within the vessel, which fluids are typically under pressure and may be volatile or environmentally hazardous. Thus, in these circumstances, it is preferable to be able to make the desired connection without the necessity of interrupting the operation of the vessel and preferably in a manner inhibiting the leakage of any fluids from the vessel.
The cutting or drilling of an opening or hole into a vessel containing fluid, typically under pressure, is referred to as xe2x80x9chot tapping.xe2x80x9d Hot tapping permits the desired connection to be made without significantly interfering with the use or operation of the vessel. Thus, hot tapping is particularly applicable to industries such as the petroleum industry where a connection may be required or desired to be made to a pipeline, while minimizing any interference with the flow of fluid through the pipeline or disruption in service, as well as inhibiting the leakage of any fluids from the pipeline.
Various tapping machines and apparatuses have been developed for drilling or cutting a hole or opening into a fluid containing vessel. Typically, the hot tapping operation is accomplished by tapping into the vessel from a valve device connected with the vessel. More particularly, the valve device may be directly mounted or attached with the outer wall of the vessel or may be mounted or attached with a standpipe or branch pipe or connection extending from the outer vessel wall to the ground surface. In either case, the valve device in place is typically not in fluid connection with the vessel, in that an opening or hole does not pre-exist. The hot tapping operation establishes the desired fluid communication with the vessel by cutting or drilling the hole or opening in the outer vessel wall.
Where no valve device pre-exists, a valve device is typically welded, clamped or otherwise mounted or attached to the outer wall of the vessel prior to proceeding with the hot tapping operation. However, in these cases where the vessel is located underground, a considerable amount of time and expense may be incurred to access or excavate the vessel to place the valve device, subsequently perform the tapping operation and then backfill the excavation.
As a result, often times, in anticipation of the potential future need to establish a further connection with the vessel, the vessel is initially placed with a pre-existing valve device to permit easier access at a later date. Where the vessel is located underground, as discussed above, in anticipation of the need for a potential future connection, the vessel may include a standpipe or branch pipe or connection extending from the outer vessel wall to the ground surface. The valve device is then connected with the standpipe at or near the ground surface for relatively easy access without the need to excavate the site.
The hot tapping operation is simply performed by mounting the hot tapping apparatus to the valve device and running the drilling or cutting tool of the tapping apparatus through the open valve device and the standpipe or branch pipe to contact the vessel and cut or drill through the vessel wall. However, where the vessel is underground, the tapping apparatus must have sufficient dimensions to permit the drilling or cutting tool to extend through the length of the standpipe to the vessel wall beneath the surface. After the opening has been cut, the drilling or cutting tool is withdrawn and the valve device is closed to prevent the leakage of any fluids from the vessel. Any pressure within the tapping apparatus may then be bled off and the tapping apparatus may be removed from the valve device.
Thus, the tapping apparatus preferably performs two primary functions. First, the apparatus supports the drilling or cutting tool such that it may drill or cut the hole or opening in the vessel wall. Second, the apparatus preferably provides a feed mechanism for advancing or retracting the drilling or cutting tool towards or away from the vessel wall. In addition, the feed mechanism is preferably relatively easy to access and operate and the overall apparatus is of a relatively strong or sturdy construction.
Various devices or apparatuses have been developed for hot tapping fluid containing vessels. However, none of these devices have been found to be completely satisfactory.
For instance, Canadian Patent No. 426,813 issued Apr. 17, 1945 to Mercier, U.S. Pat. No. 4,331,170 issued May 25, 1982 to Wendell, U.S. Pat. No. 4,332,272 issued Jun. 1, 1982 to Wendell and U.S. Pat. No. 4,680,848 issued Jun. 21, 1987 to Goldner describe a tapping apparatus in which a drill bit is rotated through a drill stem, rod or shaft having a lower end attached with the drill bit. However, the drill bit is advanced towards the vessel wall by simply applying a direct longitudinal or axial force, typically manually, at an upper end of the drill stem, rod or shaft to move the drill bit relative to the vessel wall. In other words, no particular feed mechanism is provided for advancing or retracting the drill bit.
Other forms of tapping apparatus provide for a particular feed mechanism. However, the specific construction or configuration of the feed mechanism may result in a relatively unsturdy or weakened apparatus structure. Further, the specific construction or configuration often requires the operation of the feed mechanism from a location adjacent the upper end of the apparatus, which may be difficult to access depending upon the overall length or height of the tapping apparatus.
For instance, Canadian Patent No. 531,194 issued Oct. 2, 1956 to Mueller, Canadian Patent No. 645,089 issued Jul. 17, 1962 to Milanovits et. al., and U.S. Pat. No. 2,972,915 issued Feb. 28, 1961 to Milanovits et. al., Canadian Patent No. 675,771 issued Dec. 10, 1963 to Vemoov, Canadian Patent No. 675,890 issued Dec. 10, 1963 to Vernooy, U.S. Pat. No. 3,068,726 issued Dec. 18, 1962 to Vernoov and Canadian Patent No. 1,178,830 issued Dec. 4, 1984 to Yarnell provide for an inner drilling rod, referred to as a drill stem, drill rod or boring bar, attached with the drill bit, which is contained within an outer feed mechanism in a manner such that the inner drilling rod is coaxial with the outer feed mechanism. In other words, the longitudinal axis of the inner drilling rod coincides with the longitudinal axis of the outer feed mechanism. The outer feed mechanism is variously described as an outer feed sleeve, feed tube or feed or holder nut and is configured to permit the passage of the inner drilling rod therethrough. More particularly, rotation of the outer feed mechanism produces axial movement of the inner drilling rod in order to advance or retract the drill bit relative to the outer vessel wall.
The coaxial nature of the apparatus and the need to contain the inner drilling rod within the outer feed mechanism tends to result in a relatively complex structural arrangement of the apparatus and a relatively weakened structure of the apparatus overall. Further, as in Meuller, the Milanovits et. al. references and the Vernooy references, the complexity and weakening of the structure of the apparatus may be exacerbated by further containing both the drilling rod and the feed mechanism within a single housing or chamber, which is also coaxial with the drilling rod and the feed mechanism. Typically, the feed mechanism is threadably engaged with an inner surface of the housing such that rotation of the feed mechanism relative to the housing results in axial movement of the feed mechanism and drilling rod extending therethrough.
Conversely, Canadian Patent No. 531,586 issued Oct. 9, 1956 to Hill and U.S. Pat. No. 2,601,434 issued Jun. 24, 1952 to Du Bois provide for a substantially inner feed mechanism, referred to as a feed screw and which may be combined with a feed nut. The inner feed mechanism is contained within an outer drilling rod, referred to as a boring bar assembly or a quill, attached to the drill bit, such that the outer drilling rod is coaxial with the substantially inner feed mechanism. In other words, once again, the longitudinal axis of the outer drilling rod coincides with the longitudinal axis of the inner feed mechanism. Similarly, rotation of the inner feed mechanism produces axial movement of the outer drilling rod in order to advance or retract the drill bit relative to the outer vessel wall.
Once again, the coaxial nature of the apparatus and the need to contain the inner feed mechanism within the outer drilling rod tends to result in a relatively complex structural arrangement of the apparatus and a relatively weakened structure of the apparatus overall. Further, as in Hill and Du Bois the complexity and weakening of the structure of the apparatus may be exacerbated by further containing both the drilling rod and the feed mechanism within a single housing or chamber, which is also coaxial with the drilling rod and the feed mechanism.
Furthermore, each of these tapping apparatuses provides a xe2x80x9ctop drivexe2x80x9d for the feed mechanism. In other words, the drive or power mechanism for the feed mechanism is located at an upper end of the tapping apparatus and particularly the upper end of the feed mechanism. This location tends to make access to and operation of the feed mechanism relatively difficult. In addition, Mueller, the Vemooy references, Yarnell and Hill all provide for the simultaneous rotation of the drilling rod and the advancement of the drilling rod towards the vessel wall by the feed mechanism.
Thus, there remains a need in the industry for an improved drilling apparatus for tapping into a fluid containing vessel, preferably from a valve device connected with the vessel. Preferably, the improved apparatus is relatively strong or sturdy and relatively less complex structurally as compared with known tapping machines and apparatuses. In addition, the improved apparatus is preferably comprised of a feed mechanism which is operable from a bottom or lower end of the feed mechanism for ease of access and operation.
The present invention relates to a drilling apparatus for tapping into a fluid containing vessel from a valve device connected with the vessel.
The apparatus includes a feed rod assembly which may be manipulated to move a drilling rod through a housing bore defined by a housing. The feed rod assembly is adjacent to the housing bore. In other words, the feed rod assembly is not coaxial with the drilling rod and is not contained within the housing bore.
In one aspect, the invention is a drilling apparatus for tapping into a fluid containing vessel from a valve device connected with the vessel, the apparatus comprising:
(a) a housing having a lower end adapted for attachment of the apparatus to the valve device, the housing defining a housing bore, the housing bore defining a housing bore axis;
(b) a feed rod assembly connected with the housing adjacent to the housing bore;
(c) a feed nut connected with the feed rod assembly, the feed nut defining a first bore;
(d) a drilling rod extending through the housing bore and rotatably supported in the first bore of the feed nut; and
(e) a drilling bit connected to a lower end of the drilling rod, for tapping into the vessel;
wherein manipulation of the feed rod assembly results in axial movement of the feed nut and the drilling rod relative to the housing bore axis so that the drilling rod moves through the housing bore.
The feed rod assembly may be comprised of any structure or apparatus which can be manipulated to result in axial movement of the feed nut and the drilling rod relative to the housing bore axis so that the drilling rod moves through the housing bore.
For example, the feed rod assembly may be comprised of one or more telescoping members. The members may be actuated to move the drilling rod through the housing bore. The feed rod assembly may also be comprised of one or more jacks which can be raised or lowered to move the drilling rod through the housing bore. Preferably the feed rod assembly is comprised of at least one feed rod which has a threaded exterior surface which engages a complementary threaded surface on the feed nut such that rotation of the feed rod relative to the feed nut moves the drilling rod through the housing bore.
More particularly, the feed rod assembly is preferably comprised of a first feed rod, wherein the first feed rod is rotatably connected with the housing adjacent to the housing bore, wherein the first feed rod is comprised of a threaded exterior surface, wherein the feed nut defines a second bore, wherein the second bore is comprised of a threaded interior surface which engages the threaded exterior surface of the first feed rod, and wherein rotation of the first feed rod results in axial movement of the feed nut and the drilling rod relative to the housing bore axis.
In the preferred embodiment the feed rod assembly is further comprised of a second feed rod, wherein the second feed rod is rotatably connected with the housing adjacent to the housing bore, wherein the second feed rod is comprised of a threaded exterior surface wherein the feed nut defines a third bore, wherein the third bore is comprised of a threaded interior surface which engages the threaded exterior surface of the second feed rod, and wherein rotation of the first feed rod and the second feed rod results in axial movement of the feed nut and the drilling rod relative to the housing bore axis.
In the preferred embodiment, the apparatus is further comprised of a feed rod linkage for rotatably linking the first feed rod with the second feed rod so that the first feed rod and the second feed rod rotate together. Preferably the first feed rod and the second feed rod rotate at the same rate so that the second feed rod rotates one revolution for every one revolution of the first feed rod. Preferably the amount of axial movement of the feed nut relative to the first feed rod (per revolution) is the same as the amount of axial movement of the feed nut relative to the second feed rod (per revolution). These results are achieved in the preferred embodiment by matching the pitch of the threads on the first feed rod and the second feed rod and by ensuring that the feed rod linkage provides a 1:1 linkage.
The feed rod linkage may be comprised of any structure or apparatus which can link the rotation of the first feed rod and the second feed rod such that the rate of rotation of the second feed rod relative to the rate of rotation of the second feed rod may be controlled. For example, the feed rod linkage may be comprised of a combination of belts and pulleys or intermeshing gears.
In the preferred embodiment the feed rod linkage is comprised of a first feed rod sprocket connected with the first feed rod, a second feed rod sprocket connected with the second feed rod, and a drive chain engaged with both the first feed rod sprocket and the second feed rod sprocket. A chain and sprocket assembly is preferred over a belt an pulley assembly because of the more positive control that may be maintained over the relative rotations of the first feed rod and the second feed rod by using a chain and sprocket assembly.
Preferably the drilling rod has a drilling rod axis, the first feed rod has a first feed rod axis, and the second feed rod has a second feed rod axis. In the preferred embodiment the drilling rod axis, the first feed rod axis and the second feed rod axis are all substantially parallel to each other.
Furthermore, in the preferred embodiment the drilling rod axis is substantially parallel to the housing bore axis. Ideally the drilling rod and the housing bore are coaxial. In this manner, axial movement of the feed nut relative to the first feed rod axis and the second feed rod axis results in a corresponding and equal movement of the feed nut and the drilling rod relative to the housing bore axis.
The first feed rod and the second feed rod are preferably configured relative to the drilling rod so that the drilling rod is between the first feed rod and the second feed rod. This configuration results in an amount of symmetry between the drilling rod and the feed rod assembly.
For example, a first circular plane perpendicular to the drilling rod axis may have a diameter which is defined by the intersection of the plane by the first feed rod axis and the second feed rod axis. Preferably, the drilling rod axis will intersect the first circular plane.
The apparatus may be further comprised of a support frame associated with the housing. The primary purpose of the support frame is to help to maintain alignment of the feed rod assembly relative to the drilling rod. The support frame may also serve to reinforce the apparatus, thus increasing its strength and rigidity.
The support frame may be comprised of any structure which is capable of providing some reinforcement for the apparatus. For example, the support frame may be comprised of any number of frame members. These frame members preferably help to rigidify the connection between the feed rod assembly and the housing.
In the preferred embodiment the support frame is comprised of a first frame member connected with the housing and a second frame member connected with the housing.
Preferably the first frame member has a first frame member axis and the second frame member has a second frame member axis. In the preferred embodiment the drilling rod axis, the first frame member axis and the second frame member axis are all substantially parallel to each other.
The first frame member and the second frame member are preferably configured relative to the drilling rod so that the drilling rod is between the first frame member and the second frame member. This configuration results in an amount of symmetry between the drilling rod and the support frame.
For example, a second circular plane perpendicular to the drilling rod axis may have a diameter which is defined by the intersection of the plane by the first frame member axis and the second frame member axis. Preferably, the drilling rod axis will intersect the second circular plane.
Preferably the apparatus is capable of being used for xe2x80x9chot tappingxe2x80x9d operations in which the vessel contains pressurized fluid. The apparatus may be used for tapping or hot tapping into any type of vessel. In the preferred embodiment the apparatus is intended for use for hot tapping into pipelines.
As a result, in the preferred embodiment the apparatus is further comprised of a sealing device contained within the housing bore for sealing between the housing bore and the drilling rod. Preferably the sealing device is capable of withstanding high pressure. More preferably the sealing device is also capable of withstanding high temperatures. Preferably the apparatus also includes a sealing mechanism or sealing assembly associated with the housing for sealing between the lower end of the housing and the valve device.
The feed rod assembly may be actuated in any manner which is compatible with the design of the feed rod assembly. For example, the feed rod assembly may be actuated hydraulically, pneumatically, electrically or mechanically and may be actuated manually or automatically.
Depending upon the design of the feed rod assembly, the feed nut may move with the feed rod assembly or relative to the feed rod assembly and the feed rod assembly may be actuated by rotational movement or linear or longitudinal movement. For example, if the feed rod assembly is comprised of telescoping members the feed nut may be fixedly connected with a telescoping member and may move as a result of linear movement of the feed rod assembly. In the preferred embodiment the feed rods rotate relative to the feed nut so that the feed rod assembly is actuated by rotating the feed rods.
In the preferred embodiment the feed rod assembly may be actuated by any mechanism which can rotate both the first feed rod and the second feed rod via the feed rod linkage. For example, the apparatus may be permanently equipped with a rotary drive mechanism such as a motor for rotating one or both of the first feed rod and the second feed rod. Alternatively the apparatus may be adapted such that a rotary drive mechanism such as a drill can be connected with the feed rod assembly to rotate the feed rods.
In either case, the apparatus preferably further comprises a drive attachment associated with one of the first feed rod and the second feed rod for connection with a drive mechanism in order to rotate the feed rods. This drive attachment may be comprised of any structure which provides compatibility between the feed rod assembly and the selected drive mechanism.
Preferably the feed rod assembly may be actuated by an operator from a standing position on the ground adjacent to the apparatus, thus avoiding the use of scaffolding or ladders.
Preferably this result is achieved by locating the drive attachment as close to the lower end of the housing as possible. In the preferred embodiment, the first feed rod has a lower end, the second feed rod has a lower end, and the drive attachment is associated with either the lower end of the first feed rod or the lower end of the second feed rod.
In the preferred embodiment the housing has an upper end and the feed rods and the frame members have upper ends which extend above the upper end of the housing. As a result, in the preferred embodiment the apparatus is further comprised of a top mount for the feed rod assembly and for the support frame so that the feed rods and the frame members extend between the upper end of the housing and the top mount. The feed rods and the frame members are connected with the top mount. The feed rods are rotatably connected with the top mount and the frame members are preferably fixedly connected with the top mount to enhance the rigidity of the apparatus between the housing and the top mount.
As indicated, one of the purposes of the support frame is to maintain alignment of the feed rod assembly. As a result, in the preferred embodiment the feed nut is comprised of a first frame engaging surface which is slidably engaged with the first frame member and a second frame engaging surface which is slidably engaged with the second frame member, so that the feed nut can be guided and supported by the support frame as it moves axially relative to the feed rods.
The apparatus and the feed rod assembly may be designed to provide for any range of relative axial movement of the feed nut and the drilling rod. In the preferred embodiment where the feed rods extend between the upper end of the housing and the top mount, the feed nut has a range of axial movement contained between the upper end of the housing and the top mount.